Sunday, March 15, 2015

Tylosaurus pembinensis

Tylosaurus pembinensis (Marsh, 1872)

Sauropsida

Diapsida

Lepidosauria

Squamata

Mosasauroidea

Mosasauridae

Tylosaurinae

Late Cretaceous

Central / Western United States

Length: 15 m

More than a century after Cope and Marsh first dug up fossils of this giant squamate, our view of her has changed drastically. We now know that she possessed an asymmetrical tail fluke, was countershaded, lacked a dorsal crest, and is most likely more closely related to monitor lizards than she is to snakes.